This invention relates to electrical connectors and more particularly to such connectors for supplying anode voltage to a cathode ray tube.
Cathode ray tubes require numerous electrical potentials to be applied to the electrodes of the tube. One of these, the second anode, has a very high potential applied thereto, on the order of 30 kV or more ill the case of color picture tubes. This potential is conventionally applied through the funnel by a connector hermetically sealed therein. This connector conventionally is called a second anode button. It is a substantially hollow, electrically conductive button having a thermal coefficient of expansion that substantially matches that of the glass into which it is sealed. Prior to insertion the button is oxidized so that an oxide-to-oxide bond is formed with the glass.
Recently, such anode buttons have been fabricated with an external, depending connecting pin attached thereto. The pin is welded to the bottom of the anode button and projects internally of the cathode ray tube, and it is necessary that perpendicularity be achieved if the pin is to function properly.
The connecting pins are made from wire by a cold heading process that forms an enlarged head. Thereafter the opposite end of the wire is sheared to form a connecting pin of the appropriate length. This process requires a great deal of maintenance of the cut-off or shearing tool to insure a planar condition on the end of the pin so that a critical perpendicularity of the pin to the bottom of the button can be maintained.
It is, therefore, an object of the invention to obviate the disadvantages of the prior art.
It is yet another object of the invention to provide connecting pins for achieving uniform perpendicularity.
These objects are accomplished, in one aspect of the invention, by a connecting pin for an anode, the pin compromising a body having a longitudinal axis, a contact head formed at a proximal portion of the body, a base formed at a distal portion of the body and an intermediate shank portion therebetween, all symmetrically arrayed about the longitudinal axis, the shank having a first diameter, and the contact head having at least one lateral dimension greater than the shank diameter. The base has a diameter greater than the shank diameter and has a surface that is planar and substantially orthogonal to the longitudinal axis.
Providing the pin with the expanded base insures that the base will be planar and form a proper perpendicular assembly welded to the bottom of a second anode button.